Investigation of the effect of different intensity stabilization exercises on core muscle stiffness and pain in chronic low back pain: a single-blind, randomized controlled trial.

The primary aim of this study was to investigate the effects of different intensities of spinal stabilization exercises (SSE) on the core muscle stiffness; the secondary aim was to investigate the effects of these exercises on pain and disability. Participants were randomly assigned into three groups. Group 1 (n = 16) received supervised SSE 4 days a week; group 2 (n = 17) received supervised SSE 2 days a week; and the control group (n = 17) received a home exercise program. Stiffness of transversus abdominis (TrA) measured by shear wave elastography at baseline and 12 weeks. Pain and disability evaluated by visual analog scale (VAS) and Oswestry Disability Index (ODI) at baseline, 6 weeks and 12 weeks. Post-intervention median left and right TrA stiffness were measured as group 1 = 31.4 (25.6-37.8) and 33.3 (27.6-36.2); group 2 = 27.8 (21.6-34.8) and 28.2 (21.9-35.6); control group = 19.4 (14.8-28.2) and 20.6 (15.2-30.2). The muscle stiffness of the group 1 was found to be statistically higher than the other groups (p < 0.05). Post-intervention median VAS and ODI scores were measured as group 1 = 3 (2-4) and 17 (14-26); group 2 = 3 (2-4) and 24 (16-26); control group = 4 (3-5) and 28 (20-36). The difference between the means between groups 1 and 2 was 0.63 for VAS and 7.61 for ODI. These differences were smaller than the minimal clinically important difference value. VAS was statistically lower in groups 1 and 2 than in the control group (p < 0.001). There was no statistical difference in VAS between groups 1 and 2 (p = 0.668). Group 1 improved ODI statistically more than group 2 (p = 0.002). Supervised SSE performed four days a week is statistically more effective in increasing muscle stiffness and reducing disability than exercises performed two days a week.Trial registration This study was registered in Clinical Trials on 22.04.2024 with the reference number NCT06227767. https://clinicaltrials.gov/NCT06227767 .